<html>
<style type="text/css">
.body {
  margin: 0;
  padding: 0;
}
.background {
  width: 100%;
  height: 100%;
  background-image: url(background.png);
  background-attachment: fixed;
  background-position: center;
}
</style>
<body class="body">
  <div class="background"></div>
</body>
</html>